Gramps 4.1.3-1: Database locked, can't be found.

Gramps 4.1.3-1: Database locked, can't be found.

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Hello there,
I've been working on my family tree for three months now and have had no trouble up to now. I believe I updated the program yesterday, but can't be sure.
After closing the program yesterday evening and opening it up this morning Gramps told me my database was locked and I should unlock it.
However, the database can no longer be viewed in the Family Tree manager: it's empty and the file can't be found at the location I saved it at.
The database files folder is still the grampspsdb folder.
When I try to unlock the database via cmd it tells me there is no database with such a name.

Any idea what went wrong, how can I get my database back and operational?